Lower Ball Joint bolts needed for K-H setup

hemi71x said
65-72 Kelsey Hayes, 4 piston caliper disc brake systems, DO NOT use any Nuts to attach the ball joint to the spindle.
They just thread onto the spindle with 9/16 bolts.
But i know 3 inch bolts are too long in length.
I forget the proper length of the bolts, as it's now going on 3 years time since i rebuilt my last set up.
Hardware store, grade 8 items.

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Thanks guys, The problem will be finding bolts that are threaded all the way without that shoulder, otherwise I will have to use nuts..